Multiple shadow mapping improvements (#100). See description

Changes: - Added HlmsMacroblock::mDepthClamp - Added RSC_DEPTH_CLAMP, present almost anywhere except A7, A8 iOS HW - Added shadow map pancacking using mDepthClamp to FocusedShadowCameraSetup for directional shadow maps. This tightens depth range, increasing precision and decreasing the need for 32-bit depth buffers - Fix normal offset bias heavily dependent on shadow map resolution - Point lights' normal offset bias was accidentally hardcoded - shadowConstantBias in the caster shader no longer varies implicitly due to depth range. It was a cryptic (user hostile) way of increasing bias to higher splits. - Changed default value of constantBiasScale - Changed default value of normalOffsetBias - Added autoConstantBiasScale and autoNormalOffsetBiasScale. This value adjusts the bias based on the size of the shadow camera. Shadow cameras covering more area require bigger biases. This setting is a much user-friendlier way of automatically scaling the bias to higher splits.
OGRECave · Jun 19, 2020 · 652acb3 · paroj · Sep 27, 2020 · darksylinc
1 parent 50d84a8
commit 652acb3
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Showing 16 changed files with 123 additions and 18 deletions.
diff --git a/OgreMain/include/Compositor/OgreCompositorShadowNodeDef.h b/OgreMain/include/Compositor/OgreCompositorShadowNodeDef.h
@@ -66,10 +66,21 @@ namespace Ogre
         /// Constant bias is per material (tweak HlmsDatablock::mShadowConstantBias).
         /// This value lets you multiply it 'mShadowConstantBias * constantBiasScale'
         /// per cascade / shadow map
+        ///
+        /// This is applied on top of the autocalculated bias from autoConstantBiasScale
         float constantBiasScale;
         /// Normal offset bias is per cascade / shadow map
+        ///
+        /// This is applied on top of the autocalculated bias from autoNormalOffsetBiasScale
         float normalOffsetBias;
 
+        /// 0 to disable.
+        /// Non-zero to increase bias based on orthographic projection's window size.
+        float autoConstantBiasScale;
+        /// 0 to disable.
+        /// Non-zero to increase bias based on orthographic projection's window size.
+        float autoNormalOffsetBiasScale;
+
         ShadowMapTechniques shadowMapTechnique;
 
         //PSSM params
@@ -94,8 +105,10 @@ namespace Ogre
             arrayIdx( _arrayIdx ),
             light( _light ),
             split( _split ),
-            constantBiasScale( 0.1f ),
-            normalOffsetBias( 0.00004f ),
+            constantBiasScale( 1.0f ),
+            normalOffsetBias( 168.0f ),
+            autoConstantBiasScale( 100.0f ),
+            autoNormalOffsetBiasScale( 4.0f ),
             shadowMapTechnique( t ),
             pssmLambda( 0.95f ),
             splitPadding( 1.0f ),

diff --git a/OgreMain/include/OgreCamera.h b/OgreMain/include/OgreCamera.h
@@ -190,6 +190,8 @@ namespace Ogre {
         /// Camera to use for LOD calculation
         const Camera* mLodCamera;
 
+        bool mNeedsDepthClamp;
+
         /// Whether or not the minimum display size of objects should take effect for this camera
         bool mUseMinPixelSize;
         /// @see Camera::getPixelDisplayRatio
@@ -711,6 +713,9 @@ namespace Ogre {
         */
         bool getUseMinPixelSize() const { return mUseMinPixelSize; }
 
+        void _setNeedsDepthClamp( bool bNeedsDepthClamp );
+        bool getNeedsDepthClamp( void ) const { return mNeedsDepthClamp; }
+
         /** Returns an estimated ratio between a pixel and the display area it represents.
             For orthographic cameras this function returns the amount of meters covered by
             a single pixel along the vertical axis. For perspective cameras the value

diff --git a/OgreMain/include/OgreHlmsDatablock.h b/OgreMain/include/OgreHlmsDatablock.h
@@ -77,6 +77,7 @@ namespace Ogre
     struct _OgreExport HlmsMacroblock : public BasicBlock
     {
         bool                mScissorTestEnabled;
+        bool                mDepthClamp;
         bool                mDepthCheck;
         bool                mDepthWrite;
         CompareFunction     mDepthFunc;
@@ -125,6 +126,7 @@ namespace Ogre
             //Don't include the ID in the comparision
             return  mAllowGlobalDefaults    != _r.mAllowGlobalDefaults ||
                     mScissorTestEnabled     != _r.mScissorTestEnabled ||
+                    mDepthClamp             != _r.mDepthClamp ||
                     mDepthCheck             != _r.mDepthCheck ||
                     mDepthWrite             != _r.mDepthWrite ||
                     mDepthFunc              != _r.mDepthFunc ||

diff --git a/OgreMain/include/OgreHlmsPso.h b/OgreMain/include/OgreHlmsPso.h
@@ -141,6 +141,7 @@ namespace Ogre
             ForceDisableDepthWrites     = 1u << 0u,
             InvertVertexWinding         = 1u << 1u,
             NoDepthBuffer               = 1u << 2u,
+            ForceDepthClamp             = 1u << 3u,
         };
     };
 

diff --git a/OgreMain/include/OgreRenderSystemCapabilities.h b/OgreMain/include/OgreRenderSystemCapabilities.h
@@ -228,6 +228,7 @@ namespace Ogre
         RSC_CONST_BUFFER_SLOTS_IN_SHADER = OGRE_CAPS_VALUE(CAPS_CATEGORY_COMMON_3, 10),
         RSC_TEXTURE_COMPRESSION_ASTC = OGRE_CAPS_VALUE(CAPS_CATEGORY_COMMON_3, 11),
         RSC_STORE_AND_MULTISAMPLE_RESOLVE = OGRE_CAPS_VALUE(CAPS_CATEGORY_COMMON_3, 12),
+        RSC_DEPTH_CLAMP = OGRE_CAPS_VALUE(CAPS_CATEGORY_COMMON_3, 13),
 
         // ***** DirectX specific caps *****
         /// Is DirectX feature "per stage constants" supported

diff --git a/OgreMain/src/Compositor/OgreCompositorShadowNode.cpp b/OgreMain/src/Compositor/OgreCompositorShadowNode.cpp
@@ -566,8 +566,6 @@ namespace Ogre
                     texCamera->setAutoAspectRatio( false );
                 }
 
-                texCamera->_setConstantBiasScale( itor->constantBiasScale );
-
                 if( itor->shadowMapTechnique == SHADOWMAP_PSSM )
                 {
                     assert( dynamic_cast<PSSMShadowCameraSetup*>
@@ -595,6 +593,23 @@ namespace Ogre
 
                 itShadowCamera->minDistance = itShadowCamera->shadowCameraSetup->getMinDistance();
                 itShadowCamera->maxDistance = itShadowCamera->shadowCameraSetup->getMaxDistance();
+
+                float fAutoConstantBiasScale = 1.0f;
+                if( itor->autoConstantBiasScale != 0.0f )
+                {
+                    if( texCamera->getProjectionType() == PT_ORTHOGRAPHIC )
+                    {
+                        const Real orthoSize = std::max( texCamera->getOrthoWindowWidth(),
+                                                         texCamera->getOrthoWindowHeight() );
+                        float autoFactor = orthoSize / light->getShadowFarDistance();
+                        fAutoConstantBiasScale = 1.0f + autoFactor * itor->autoConstantBiasScale;
+                    }
+                }
+                texCamera->_setConstantBiasScale( itor->constantBiasScale * fAutoConstantBiasScale );
+
+                const RenderSystemCapabilities *caps = mRenderSystem->getCapabilities();
+                texCamera->_setNeedsDepthClamp( light->getType() == Light::LT_DIRECTIONAL &&
+                                                caps->hasCapability( RSC_DEPTH_CLAMP ) );
             }
             //Else... this shadow map shouldn't be rendered and when used, return a blank one.
             //The Nth closest lights don't cast shadows
@@ -962,7 +977,25 @@ namespace Ogre
     //-----------------------------------------------------------------------------------
     float CompositorShadowNode::getNormalOffsetBias( const size_t shadowMapIdx ) const
     {
-        return mDefinition->mShadowMapTexDefinitions[shadowMapIdx].normalOffsetBias;
+        const ShadowTextureDefinition &shadowMapDef =
+            mDefinition->mShadowMapTexDefinitions[shadowMapIdx];
+
+        float fAutoConstantBiasScale = 1.0f;
+        if( shadowMapDef.autoNormalOffsetBiasScale != 0.0f )
+        {
+            Light const *light = mShadowMapCastingLights[shadowMapDef.light].light;
+            OGRE_ASSERT_HIGH( light && "Can't call this function if isShadowMapIdxActive is false!" );
+
+            const Camera *texCamera = mShadowMapCameras[shadowMapIdx].camera;
+            if( texCamera->getProjectionType() == PT_ORTHOGRAPHIC )
+            {
+                const Real orthoSize =
+                    std::max( texCamera->getOrthoWindowWidth(), texCamera->getOrthoWindowHeight() );
+                float autoFactor = orthoSize / light->getShadowFarDistance();
+                fAutoConstantBiasScale = 1.0f + autoFactor * shadowMapDef.autoNormalOffsetBiasScale;
+            }
+        }
+        return shadowMapDef.normalOffsetBias;
     }
     //-----------------------------------------------------------------------------------
     void CompositorShadowNode::setLightFixedToShadowMap( size_t shadowMapIdx, Light *light )

diff --git a/OgreMain/src/OgreCamera.cpp b/OgreMain/src/OgreCamera.cpp
@@ -56,6 +56,7 @@ namespace Ogre {
         mCullFrustum(0),
         mUseRenderingDistance(true),
         mLodCamera(0),
+        mNeedsDepthClamp(false),
         mUseMinPixelSize(false),
         mPixelDisplayRatio(0),
         mConstantBiasScale(1.0f)
@@ -1131,6 +1132,11 @@ namespace Ogre {
 
     }
     //-----------------------------------------------------------------------
+    void Camera::_setNeedsDepthClamp( bool bNeedsDepthClamp )
+    {
+        mNeedsDepthClamp = bNeedsDepthClamp;
+    }
+    //-----------------------------------------------------------------------
     void Camera::_resetRenderedRqs( size_t numRqs )
     {
         mRenderedRqs.clear();

diff --git a/OgreMain/src/OgreHlms.cpp b/OgreMain/src/OgreHlms.cpp
@@ -2031,6 +2031,11 @@ namespace Ogre
             //Without culling there's nothing to invert, we don't need to hold a strong reference.
             pso.pass.strongMacroblockBits &= ~HlmsPassPso::InvertVertexWinding;
         }
+        if( pso.macroblock->mDepthClamp )
+        {
+            //Macroblock already enabled depth clamp, we don't need to hold a strong reference.
+            pso.pass.strongMacroblockBits &= ~HlmsPassPso::ForceDepthClamp;
+        }
 
         if( pso.pass.hasStrongMacroblock() )
         {
@@ -2048,6 +2053,9 @@ namespace Ogre
                 prepassMacroblock.mCullMode = prepassMacroblock.mCullMode == CULL_CLOCKWISE ?
                             CULL_ANTICLOCKWISE : CULL_CLOCKWISE;
             }
+            //Force depth clamp. Probably a directional shadow caster pass
+            if( pso.pass.strongMacroblockBits & HlmsPassPso::ForceDepthClamp )
+                prepassMacroblock.mDepthClamp = true;
 
             pso.macroblock = mHlmsManager->getMacroblock( prepassMacroblock );
         }
@@ -3075,6 +3083,9 @@ namespace Ogre
         if( sceneManager->getCurrentPrePassMode() == PrePassUse )
             passPso.strongMacroblockBits |= HlmsPassPso::ForceDisableDepthWrites;
 
+        if( sceneManager->getCamerasInProgress().renderingCamera->getNeedsDepthClamp() )
+            passPso.strongMacroblockBits |= HlmsPassPso::ForceDepthClamp;
+
         const bool invertVertexWinding = mRenderSystem->getInvertVertexWinding();
 
         if( (renderPassDesc->requiresTextureFlipping() && !invertVertexWinding) ||

diff --git a/OgreMain/src/OgreHlmsDatablock.cpp b/OgreMain/src/OgreHlmsDatablock.cpp
@@ -54,6 +54,7 @@ namespace Ogre
     HlmsMacroblock::HlmsMacroblock() :
         BasicBlock( BLOCK_MACRO ),
         mScissorTestEnabled( false ),
+        mDepthClamp( false ),
         mDepthCheck( true ),
         mDepthWrite( true ),
         mDepthFunc( CMPF_LESS_EQUAL ),

diff --git a/OgreMain/src/OgreShadowCameraSetupFocused.cpp b/OgreMain/src/OgreShadowCameraSetupFocused.cpp
@@ -290,6 +290,13 @@ namespace Ogre
 
         vMin.z = Ogre::min( vMin.z, vMinCamFrustumLS.z );
 
+        const RenderSystemCapabilities *caps = Root::getSingleton().getRenderSystem()->getCapabilities();
+        if( caps->hasCapability( RSC_DEPTH_CLAMP ) )
+        {
+            // We can only do shadow pancaking (increasing precision) if depth clamp is supported
+            vMax.z = Ogre::max( vMax.z, vMaxCamFrustumLS.z );
+        }
+
         //Some padding
         vMax += 1.5f;
         vMin -= 1.5f;

diff --git a/RenderSystems/Direct3D11/src/OgreD3D11RenderSystem.cpp b/RenderSystems/Direct3D11/src/OgreD3D11RenderSystem.cpp
@@ -1203,6 +1203,8 @@ namespace Ogre
             rsc->setCapability(RSC_UAV);
         }
 
+        rsc->setCapability(RSC_DEPTH_CLAMP);
+
         rsc->setCapability(RSC_HWRENDER_TO_TEXTURE);
         rsc->setCapability(RSC_TEXTURE_FLOAT);
 
@@ -2301,7 +2303,7 @@ namespace Ogre
         rasterDesc.SlopeScaledDepthBias = newBlock->mDepthBiasSlopeScale * biasSign;
         rasterDesc.DepthBiasClamp   = 0;
 
-        rasterDesc.DepthClipEnable  = true;
+        rasterDesc.DepthClipEnable  = !newBlock->mDepthClamp;
         rasterDesc.ScissorEnable    = newBlock->mScissorTestEnabled;
 
         rasterDesc.MultisampleEnable     = true;

diff --git a/RenderSystems/GL3Plus/src/OgreGL3PlusRenderSystem.cpp b/RenderSystems/GL3Plus/src/OgreGL3PlusRenderSystem.cpp
@@ -399,6 +399,12 @@ namespace Ogre {
             rsc->setCapability(RSC_TYPED_UAV_LOADS);
         }
 
+        if( mHasGL43 || mGLSupport->checkExtension( "GL_ARB_depth_clamp" ) ||
+            mGLSupport->checkExtension( "GL_NV_depth_clamp" ) )
+        {
+            rsc->setCapability( RSC_DEPTH_CLAMP );
+        }
+
         if( mGLSupport->checkExtension( "GL_ARB_shader_viewport_layer_array" ) )
             rsc->setCapability( RSC_VP_AND_RT_ARRAY_INDEX_FROM_ANY_SHADER );
 
@@ -2054,6 +2060,14 @@ namespace Ogre {
 
         _setDepthBias( macroblock->mDepthBiasConstant, macroblock->mDepthBiasSlopeScale );
 
+        if( macroblock->mDepthClamp )
+        {
+            OCGE( glEnable( GL_DEPTH_CLAMP ) );
+        }
+        else
+        {
+            OCGE( glDisable( GL_DEPTH_CLAMP ) );
+        }
 
         //Cull mode
         if( pso->cullMode == 0 )

diff --git a/RenderSystems/Metal/src/OgreMetalRenderSystem.mm b/RenderSystems/Metal/src/OgreMetalRenderSystem.mm
@@ -378,9 +378,12 @@ of this software and associated documentation files (the "Software"), to deal
 #if OGRE_PLATFORM == OGRE_PLATFORM_APPLE_IOS
         if( [mActiveDevice->mDevice supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily3_v2] )
             rsc->setCapability(RSC_STORE_AND_MULTISAMPLE_RESOLVE);
+        if( [mActiveDevice->mDevice supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily4_v1] )
+            rsc->setCapability(RSC_DEPTH_CLAMP);
 #else
         if( [mActiveDevice->mDevice supportsFeatureSet:MTLFeatureSet_OSX_GPUFamily1_v2] )
             rsc->setCapability(RSC_STORE_AND_MULTISAMPLE_RESOLVE);
+        rsc->setCapability(RSC_DEPTH_CLAMP);
 #endif
 
 #if OGRE_PLATFORM == OGRE_PLATFORM_APPLE_IOS
@@ -2041,6 +2044,11 @@ of this software and associated documentation files (the "Software"), to deal
                                      slopeScale:pso->macroblock->mDepthBiasSlopeScale * biasSign
                                      clamp:0.0f];
         [mActiveRenderEncoder setCullMode:metalPso->cullMode];
+        if( @available( iOS 11.0, * ) )
+        {
+            [mActiveRenderEncoder setDepthClipMode:pso->macroblock->mDepthClamp ? MTLDepthClipModeClamp
+                                                                                : MTLDepthClipModeClip];
+        }
 
         if( mPso != metalPso )
         {

diff --git a/Samples/Media/Hlms/Common/Any/ShadowCaster_piece_vs.any b/Samples/Media/Hlms/Common/Any/ShadowCaster_piece_vs.any
@@ -4,9 +4,9 @@
 @property( hlms_shadowcaster )
 	@piece( DoShadowCasterVS )
 		@property( hlms_no_reverse_depth || hlms_shadowcaster_point )
-			float shadowConstantBias = uintBitsToFloat( worldMaterialIdx[inVs_drawId].y );
+			float shadowConstantBias = uintBitsToFloat( worldMaterialIdx[inVs_drawId].y ) * passBuf.depthRange.y;
 		@else
-			float shadowConstantBias = -uintBitsToFloat( worldMaterialIdx[inVs_drawId].y );
+			float shadowConstantBias = -uintBitsToFloat( worldMaterialIdx[inVs_drawId].y ) * passBuf.depthRange.y;
 		@end
 
 		@property( !hlms_shadow_uses_depth_texture && !hlms_shadowcaster_point && !exponential_shadow_maps )

diff --git a/Samples/Media/Hlms/Pbs/Any/ShadowMapping_piece_ps.any b/Samples/Media/Hlms/Pbs/Any/ShadowMapping_piece_ps.any
@@ -133,7 +133,7 @@
 @piece( DeclShadowSamplingFuncs )
 	@foreach( 2, m )
 		// Perform normal offset bias. See https://github.com/OGRECave/ogre-next/issues/100
-		INLINE float3 getNormalOffsetBias( float3 geomNormal, float3 lightDir,
+		INLINE float3 getNormalOffsetBias( float3 geomNormal, float3 lightDir, float normalOffsetBias,
 										   float shadowMapTexSize, float depthRange
 		@property( @m == 0 )
 										   )
@@ -147,7 +147,7 @@
 				shadowMapTexSize /= maxUV.x - minUV.x;
 			@end
 
-			return ( ( 1.0f - tmpNdotL ) * (0.00004f) * geomNormal.xyz * shadowMapTexSize );
+			return ( ( 1.0f - tmpNdotL ) * normalOffsetBias * geomNormal.xyz * shadowMapTexSize );
 		}
 	@end
 @foreach( 4, m )
@@ -159,12 +159,12 @@
 								float4 psPosLN, float4 invShadowMapSize, float2 minUV, float2 maxUV )
 	@end @property( @m == 2 )
 		INLINE float getShadowPoint( @insertpiece( TEXTURE2DSHADOW ) shadowMap, @insertpiece( SamplerShadow )
-									 float3 geomNormal,
-									 float3 posVS, float3 lightPos, float4 invShadowMapSize, float2 invDepthRange
+									 float3 geomNormal, float normalOffsetBias,
+									 float3 posVS, float3 lightPos,float4 invShadowMapSize, float2 invDepthRange
 									 PASSBUF_ARG_DECL )
 	@end @property( @m == 3 )
 		INLINE float getShadowPoint( @insertpiece( TEXTURE2DSHADOW ) shadowMap, @insertpiece( SamplerShadow )
-									 float3 geomNormal,
+									 float3 geomNormal, float normalOffsetBias,
 									 float3 posVS, float3 lightPos, float4 invShadowMapSize, float2 invDepthRange,
 									 float2 minUV, float2 maxUV, float2 lengthUV
 									 PASSBUF_ARG_DECL )
@@ -185,11 +185,11 @@
 	@else
 		//Point lights
 		float3 cubemapDir = posVS.xyz - lightPos.xyz;
-		cubemapDir += getNormalOffsetBias( geomNormal, cubemapDir,
+		cubemapDir += getNormalOffsetBias( geomNormal, cubemapDir, normalOffsetBias,
 				@property( @m == 2 )
-										   invShadowMapSize.z, invDepthRange.y );
+										   invShadowMapSize.x, invDepthRange.y );
 				@else
-										   invShadowMapSize.z, invDepthRange.y, minUV, maxUV );
+										   invShadowMapSize.x, invDepthRange.y, minUV, maxUV );
 				@end
 
 		float fDepth = length( cubemapDir );
@@ -438,7 +438,8 @@
 	@piece( DarkenWithShadowPoint )
 		* getShadowPoint( hlms_shadowmap@value(CurrentShadowMap), @insertpiece( UseSamplerShadow )
 						  pixelData.geomNormal,
-						  inPs.pos.xyz, light0Buf.lights[@counter(CurrentPointLight)].position.xyz,
+						  passBuf.shadowRcv[@value(CurrentShadowMap)].normalOffsetBias,
+						  inPs.pos.xyz, light0Buf.lights[@value(CurrentPointLight)].position.xyz,
 						  passBuf.shadowRcv[@value(CurrentShadowMap)].invShadowMapSize,
 						  passBuf.shadowRcv[@value(CurrentShadowMap)].shadowDepthRange.xy
 						  hlms_shadowmap@counter(CurrentShadowMap)_uv_param PASSBUF_ARG )

diff --git a/Samples/Media/Hlms/Pbs/Any/ShadowMapping_piece_vs.any b/Samples/Media/Hlms/Pbs/Any/ShadowMapping_piece_vs.any
@@ -58,7 +58,7 @@
 			@property( !hlms_shadowmap@n_is_point_light )
 				@property( !skip_normal_offset_bias_vs )
 					normalOffsetBias = getNormalOffsetBias( worldNorm, outVs.normal, shadowMap@nLightDir,
-															passBuf.shadowRcv[@n].invShadowMapSize.z,
+															passBuf.shadowRcv[@n].invShadowMapSize.x,
 															passBuf.shadowRcv[@n].shadowDepthRange.y,
 															passBuf.shadowRcv[@n].normalOffsetBias
 															hlms_shadowmap@n_uv_param );